• Energy Research

This study investigates temperature and light impact on the ability of Micractinium pusillum microalgae to mitigate CO2 and produce bioenergy in semi-continuous mode. Microalgae were exposed to temperatures (15, 25, and 35 °C) and light intensities (50, 350, and 650 μmol m-2 s-1), including two temperature cycles, 25 °C had the maximum growth rate, with no significant difference at 35 °C and light intensities of 350 and 650 μmol m-2 s-1. 15 °C temperature and 50 μmol m-2 s-1 light intensity reduced growth. Increased light intensity accelerated growth, CO2 utilization with carbon and bioenergy accumulation. Microalgae demonstrate rapid primary metabolic adjustment and acclimation reactions in response to changes in light and temperature conditions. Temperature correlated positively with carbon and nitrogen fixation, CO2 fixation, and carbon accumulation in the biomass, whereas there was no correlation found between light. In the temperature regime experiment, higher light intensity boosted nutrient and CO2 utilization, carbon buildup, and biomass bioenergy.

Abstract In this work, catalytic upgrading was carried out to enhance the yield and quality of castor seed pyrolytic oil. The influence of catalytic vapour cracking of castor seed was performed over Kaolin, CaO and ZnO catalysts at various weight percentage of loading. This study confirmed that the yield varied with catalyst type and its amount of loading. The maximum pyrolysis yield of oil was obtained about 66.4 wt.%, 64.9 wt.% and 65.8 wt.% at 15 wt.% CaO and Kaolin and 10 wt.% ZnO respectively. The effect of catalyst on fuel properties were studied at that catalyst loading where the yield of pyrolytic liquid was higher. The fuel properties of castor seed thermal and catalytic pyrolytic oil were compared. The cracking of castor seed pyrolytic vapour over the bed of catalysts proved to enhance the fuel properties of pyrolytic oil for all catalysts. In comparison with ZnO, CaO and Kaolin found to have significant effect on enhancing the fuel properties in terms of viscosity, pH, calorific value and pour point. It was observed that in catalytic pyrolytic oil the number of acidic groups significantly reduced as they got converted to esters compared to thermal pyrolytic oil. The increase in the formation of nitriles and aromatics content in the catalytic pyrolytic oil was also noticed which were comparatively less in the thermal pyrolytic oil.

Phthalic acid is an industrial chemical and it comes under the domain of endocrine disrupting chemicals (EDCs). Green solvents such as ionic liquids (ILs) posses good extractable capabilities for EDCs. COSMO–RS methodology is a widely accepted method for the design or selection of ionic liquids. COSMO–RS is a quantum chemical based method based on COSMO polarization charge densities. In this work the model has been used to screen the potential ionic liquids for the removal of phthalic acid from water. Five group of ILs with cations such as phosphonium, imidazolium, pyridinium, pyrolidinium and ammonium based were screened at infinite dilution. A total of 34 cations and 29 anions i.e. 986 possible ILs were screened and their selectivities and capacities predicted. The selectivities of the screened ILs are : phosphonium > pyrolidinium > imidazolium > ammonim > pyridinium. Some of the ionic liquids with selectivities were [TBP][CF3SO3] (16057), [OMPYR][BF4] (13265), [C4DMIM][CF3SO3] (11678), [MNH][DEC] (9650) and [C8MPY][CF3SO3] (4735). Experimental validation was done by comparing experimental logarithmic octanol–water partition coefficient values (Log Kow) with COSMO–RS predicted data on phthalic acid. The results of this study suggested that the ILs can be a possible substitute for the treatment of organic effluent rich water and wastewater

The process of combustion and pyrolysis of coal can be considered to be convoluted where numerous intermediates are expected to form during the course of the reaction.

Abstract Thermal pyrolysis of the Cassia siamea seed was carried out in a fixed bed reactor in the temperature range of 450 °C and 575 °C at a heating rate of 50 °C min−1. The reactor was maintained inert using nitrogen gas at a flow rate of 40 mL min−1. It was observed that the highest yield of pyrolytic liquid was 50.21% obtained at 550 °C which includes 39.86 wt% of organic liquid (oil) and 10.35 wt% of aqueous liquid. The fuel properties of pyrolytic oil confirmed that the oil was slightly basic with a pH of 8.75, having viscosity and calorific value of about 373 cSt and 30.18 MJ kg−1 respectively. The GC-MS based composition analysis quantified the occurrence of many valuable bio-chemicals such as heptadecanenitrile, 1,2-benzene dicarboxylic acid, butyl octyl ester, phenol, p-cresol as major compounds.

Bio-energy from lignocellulosic biomass is cleaner, sustainable, and one of the renewable energy sources that could help meet some of our energy demand. Unlike fossil fuels, it can be grown and used repeatedly and its use can replace the fossil fuels. In addition to this, these materials are easily available either in the form of agricultural waste or forest residues and are economically viable. The current study focuses on physico-chemical characterisation of three commonly available lignocellulosic biomasses of north-east India such as Castor (Ricinus communis), Jatropha (Jatropha curcas), and Miscanthus (Miscanthus sinensis) for second generation biofuels production. Ultimate analysis (CHNSO), thermogravimetric analysis, X-ray diffraction, Fourier transformation infrared (FTIR), and oxygen bomb calorimeter techniques were used to characterise the above mentioned three lignocellulose biomasses. It was found that the cellulose content of three biomasses varied from 40% to 44%, hemicellulose content from 8% to 14%, and lignin content varied from 21% to 30%. Chemical structure of lignocellulose is studied through FTIR. The crystallinity index of Castor and Jatropha is similar, i.e., ∼69%, where as crystallinity index of Miscanthus was 72%. Due to the presence of higher carbon and cellulose content along with less moisture (10%–12%), ash (5%–10%), sulphur (0.1%–0.8%), and extractives (12%–20%) make them a very good source for production of alcoholic fuels through a biochemical route.

This work presents the thermochemical characterization of some nonconventional oil containing seeds. The non-edible and less-edible oil seeds such as Mahua (Madhuca indica), Karanja (Pongamia pinnata), Niger (Hyoscyamus L. Niger), and Linseed (Linum usitatissimum) were characterized on the basis of their degradation profile, oil percentage, cellulose, hemicelluloses, lignin, and mineral content. TGA analysis confirmed that the active pyrolytic zone for all the seeds lies in the temperature range between 150 and 450 °C. It was observed that these seeds contain maximum percent of oil/extractives such as Mahua: 57.16%, Karanja: 53.19%, Niger: 39.75%, and Linseed: 33.55%. The result indicated that these seeds contains higher amount of celluloses than that of hemicelluloses and lignin. The elemental analysis confirmed that these types of biomasses are suitable for pyrolysis due to the presence of less sulphur, less moisture, and higher volatile matter content. The suitability as a feed for fuel production was observed from the relation between O/C and H/C ratio from the Van Krevelen diagram.

Developing an efficient photobioreactor (PBR) and reducing freshwater dependence are among the significant challenges for generating 3rd generation biomass feedstock. Addressing these, the present study focused on developing a modified airlift (MoAL) PBR. Its performance was further evaluated and compared with the traditional airlift PBR by cultivating microalgae in dark fermentation spent wash. Lower mixing time and higher interfacial mass transfer coefficient was observed in the MoAL PBR having a perforated draft tube. Experimentally, the MoAL exhibited the maximum biomass concentration of 3.18 g L-1, which was 30% higher than that of the conventional airlift PBR. The semi-continuous operation of the MoAL (with water recycling) achieved the maximum biomass productivity of 0.83 g L-1 d-1, two folds superior to that of batch culture. The comprehensive biomass characterization (proximate, ultimate, and thermochemical) further confirmed its potential for bioenergy application. Considering that, hydrothermal liquefaction of the biomass resulted in a maximum biocrude yield of 31% w/w with a higher heating value (HHV) of 36.6 MJ kg-1. In addition, the biocrude comprised 66.6% w/w lighter fraction (<343 °C), including 21.5% w/w of heavy naphtha, 20.5% w/w of kerosene, and 24.6% w/w of diesel. The results can help develop sustainable technology for simultaneous wastewater remediation and biocrude production.

Abstract Mango ( Mangifera indica ) is one of the popular fruits in India and many other tropical countries also. Mango seed weight is 30 − 45% of the total fruit weight which completely goes off as waste. In this study, Mango seed kernel (MSK) and Mango seed shell (MSS) were selected as a feed for pyrolysis for the production of bio-chemicals. Conventional pyrolysis of MSK and MSS was carried out in the range between 673 to 873 K temperatures at a heating rate of 25 K min −1 . The optimum temperature for maximum yield of pyrolytic liquid was 823 K and 848 K for MSK and MSS with the corresponding yield of pyrolytic liquid of about 32.37% and 52.57% respectively. The composition analysis of MSK and MSS pyrolytic liquid revealed the presence of various valuable chemicals. It was noticed that MSS pyrolytic liquid contains about 27.63% d -allose, which is a rare sugar, whereas MSK contains 13.27% of levoglucosan along with furfural, furan, alcohol, aldehyde, benzene and various alkanes.